1. Field of the Invention
This invention relates generally to pressure measurement in a gas storage system and, more particularly, to a method and mechanization which replaces one of two redundant pressure sensors in a gas storage system with a pressure switch, uses an adaptive algorithm to monitor the on-off cycling of the pressure switch in comparison to a signal from the remaining pressure sensor, and ensures that output from a regulator in the gas storage system is within an expected range of pressure.
2. Discussion of the Related Art
Fuel cell vehicles are expected to increase in popularity in the automotive marketplace. Fuel cell vehicles offer several desirable features, such as virtually pollution-free emissions, and avoiding vehicle usage of petroleum fuels. A key component of fuel cell vehicles is the hydrogen storage system, which stores the hydrogen gas used as a fuel by most fuel cell vehicles. Hydrogen storage systems typically consist of one or more interconnected pressure vessels for storing gaseous hydrogen, along with numerous valves, gauges, and fittings necessary for operation of the hydrogen storage system.
Fuel cells require a reliable source of hydrogen gas at a prescribed pressure. A pressure regulator is used to reduce the pressure of the hydrogen gas from the high pressure at which it is stored in the vessels to the lower pressure required by the fuel cell. In order to ensure that the pressure regulator is working properly, it is necessary to measure the pressure at the outlet of the pressure regulator. For redundancy, two pressure sensors are typically used to measure the pressure of the hydrogen gas output from the regulator. While this arrangement provides the reliability and redundancy needed, the cost and complexity of using two pressure sensors, along with the associated wiring and controller connections, are significant.
It would be desirable to replace one of the pressure sensors downstream of the pressure regulator with a simpler and lower cost device. Such an implementation would not only lower the cost of the hydrogen storage system, it could also improve the reliability by simplifying assembly and eliminating wiring connections and other potential fault sources.